Linear bearings are known that have a carrier body, on which pairs of tracks associated with one another and defined by lateral guide means and on which tracks roller elements move are formed. One of them, the load track, is associated with the supporting roller elements, and the other, the return track or path, is arranged for returning the unloaded roller elements; the two tracks are joined together at their ends by essentially U-shaped roller element deflection tracks, forming a closed path.
Linear bearings of this type are known in many kinds of embodiments. The roller elements may be balls, rollers or drum-like elements, and so forth, which are located one behind the other on the load track for a pressure column. In other conventional embodiments, however, the roller elements are kept spaced apart from one another by special provisions. For instance, the roller-like roller elements, carrying bearing journals on the ends, are supported on these journals in chain links, resulting in an endless interlocking structure in the manner of a "pull chain". A fundamental feature of these linear bearings is that the roller elements must be guided very accurately on the tracks, because otherwise they jam against one another, or in the case of roller elements in the form of rollers they tilt or wobble. Such phenomena cause rough operation, vibration, and so-called stick-slip effects, and so forth, which moreover entail increased wear and thus shorten the service life of the linear bearing.
For production reasons, it is necessary as a rule to produce the roller element deflectors disposed on the ends of the load track as separate parts that are secured to the carrier body and have the deflection tracks for the roller elements. In order to guide the roller elements on the substantially U-shaped deflection path, multiple-piece deflector devices are often necessary, the individual parts of which are held together by clamping shackles and the like. Because of their complicated shape, the parts are certainly not made of the same material as the carrier bodies (which as a rule are of steel); instead, materials that are readily molded and more favorable in cost are used, such as aluminum, plastic, brass, and so forth.
Thermal changes in state, caused for instance by increased operating temperatures, can cause displacements and variable changes in length of these parts of the deflector devices relative to one another and in comparison with the carrier body, with the result that the very close tolerances that are indispensible for satisfactory lateral guidance of the roller elements are exceeded, with the disadvantageous effects noted. Since the deflector devices are mounted on the carrier bodies on the face end, so that their face dividing them from the carrier body is located directly at the end of the load track (see FIG. 6 of German Patent 33 03 832 to Teramachi, for instance), the transition point between the load track and the deflection track is at an intrinsically highly . unfavorable point, at which the roller elements traveling on the load track, for instance, are relieved and in this process undergo a certain elastic deformation. Because of the close tolerance in terms of lateral guidance of the roller elements, these linear bearings therefore entail relatively high production expense, and may possibly require re-machining after assembly in the region of the roller element deflections.